JP2008146934A - Vacuum switchgear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress that a shaft of a bolt of a connecting part to connect an extraction conductor and a circuit conductor is fastened diagonally to the axis of a screw hole into which the bolt is screwed. <P>SOLUTION: This has the screw hole 12 protruded and installed at an extraction conductor 6b, a bolt 9 which is screwed into the screw hole through a through hole 8b formed in the circuit conductor 8 corresponding to the screw hole 12 and which tighten the circuit conductor and the extraction conductor, and a pan spring 10 interposed and installed between the head of the bolt and the circuit conductor. The tip part 9a of a small diameter into which the bolt is screwed, a base part 9b of a large diameter into which the bolt is not screwed and a taper part 9c to link the tip part and the base part are formed. In the screw hole 12, the screw part 12a corresponding to the tip part of the bolt, a diameter-expanded part 12b which corresponds to the base part of the bolt and into which the bolt is not screwed, and a hole stepping part 12c which is formed corresponding to the taper part of the bolt are formed. The bolt is tightened by aligning the axial center of the screw hole at the taper part when the bolt is screwed into the screw hole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vacuum switchgear, and more specifically, to a structure of a connection portion between a fixed electrode or a movable electrode and a circuit conductor.

  The vacuum switch gear stores the fixed electrode and the movable electrode facing each other in the vacuum container, and the fixed electrode and the movable electrode are each drawn out of the vacuum container by a rod-shaped lead conductor, and the lead conductor of each electrode is operated to open and close Each circuit conductor is connected to the target circuit conductor. Also, the lead conductor of the movable electrode is connected to an open / close mechanism that drives the movable electrode at a high speed in the contact / separation direction with respect to the fixed electrode, and is slidably and airtightly supported by the partition of the vacuum vessel via a guide member Has been.

  In addition, as described in Patent Document 1, for example, the lead conductor of the fixed electrode abuts the end face of the rod-shaped lead conductor on the plate-like circuit conductor, and inserts a bolt from a through hole provided in the circuit conductor. The bolt is screwed into a bag-like screw hole provided on the end face of the lead conductor and tightened so that the circuit conductor is sandwiched between the bolt head and the lead conductor.

JP2006-238522A

  However, the connection structure in which the lead conductor of the fixed electrode is fastened to the circuit conductor with a bolt is that the screw thread of the bolt and the screw hole is formed in a spiral shape, and there is a small play between the bolt and the screw thread of the screw hole. Therefore, the bolt shaft is tightened obliquely with respect to the screw hole shaft. As a result, the tightening force applied to the lead conductor and the circuit conductor varies depending on the circumferential position of the bolt head, the contact state between the lead conductor and the circuit conductor is biased, and a partial gap is generated on the contact surface. .

  In order to eliminate such a gap between the conductors, it is conceivable to increase the tightening force of the bolt. However, since the fixed electrode, the movable electrode, and the circuit conductor are not only the strength member but also the current-carrying member, a copper material having a high conductivity is usually used, and the thread formed on the copper material is a general steel material. Since the allowable shearing force is lower than that, there is a limit to increasing the tightening force.

  In addition, even if the tightening force is increased, the contact between the conductors of the connection portion is increased and a surface pressure concentration portion is generated in the conductor, so that the relaxation of the conductor of the connection portion generally formed of a copper material having high conductivity is achieved. As a result, the axial force of the bolt may be reduced, leading to loosening of the bolt. In particular, during operation for a long period of time, the lead conductor is subjected to a heat cycle due to turning on and off of the current by the opening and closing operation, and is repeatedly subjected to a large impact by the opening and closing operation. As a result, loosening of the bolts of the connecting portion proceeds, and a further gap is generated between the conductors of the connecting portion, which may shorten the mechanical life of the vacuum switch gear.

  Furthermore, depending on the vacuum switch gear, like the ground switch described in Patent Document 1, there are cases in which the periphery of the connection portion between the vacuum vessel and the lead conductor and the circuit conductor is molded with resin. In this case, if there is a gap between the conductors of the connecting portion, the molding resin may enter the gap when the resin is molded. If the mold resin enters between the conductors of the connecting portion, the electrical resistance between the conductors increases, which may shorten the life of the vacuum switchgear.

  In particular, if the resin penetrates between the conductors of the connection part when molding the resin, the resin that has entered due to the impact associated with the opening and closing operation of the fixed electrode and the movable electrode is crushed, and the resin powder is between the conductors of the connection part. There is a problem that the electrical resistance of the connecting portion is increased due to the gap.

  A problem to be solved by the present invention is to prevent the bolt shaft of the connecting portion connecting the lead conductor and the circuit conductor from being obliquely tightened with respect to the screw hole shaft into which the bolt is screwed.

  The vacuum switchgear of the present invention that solves the above problems includes a vacuum vessel, a fixed electrode and a movable electrode that are housed facing each other in the vacuum vessel, an opening / closing mechanism that contacts and separates the movable electrode from the fixed electrode, A rod-shaped lead conductor that passes through the wall of the vacuum vessel and leads the fixed electrode to the outside; and a connection portion that connects the lead conductor to an external circuit conductor. A screw hole formed in the conductor, a through hole formed in the circuit conductor corresponding to the screw hole, and a bolt that is screwed into the screw hole through the through hole and fastens the circuit conductor and the lead conductor And an elastic member provided between the head of the bolt and the circuit conductor, and the bolt is threaded and has a small-diameter tip and a threaded portion. No large diameter base, the tip and the A screw portion corresponding to a tip portion of the bolt, a diameter-expanded portion not threaded corresponding to a base portion of the bolt, and the bolt. It is characterized by having a hole step portion formed so as to correspond to the step portion so that the step portion contacts.

  With this configuration, when the bolt is screwed into the screw hole, the bolt step comes into contact with the hole step of the screw hole and the tightening stops, but the bolt shaft and screw hole at this tightening stop position are stopped. The axes are coincident or parallel. The bolt tightening force at this time depends on the elastic force of the elastic member, and the tightening force applied to the lead conductor and the circuit conductor is equalized regardless of the circumferential position of the bolt head, and the contact surface between the lead conductor and the circuit conductor It is possible to suppress the occurrence of partial gaps. Therefore, without increasing the bolt tightening force, the contact between the conductors of the connecting portion can be suppressed, and the surface pressure concentration portion does not occur. Therefore, the decrease in the axial force of the bolt due to the relaxation of the conductor can be suppressed. Bolts can be prevented from loosening. As a result, it is possible to suppress the looseness of the bolts at the connecting portion even when a large impact is repeatedly received by the opening / closing operation, and it is possible to prevent the mechanical life of the vacuum switch gear from being shortened.

  In the present invention, it is preferable to form the stepped portion of the bolt and the hole stepped portion of the screw hole at a position where they abut within the range of elastic deformation of the elastic member. Moreover, it is preferable that a bolt step part and a hole step part are formed orthogonally to a bolt axis | shaft and a screw hole axis | shaft.

  Also, the bolt step should be a tapered taper formed between the base and the tip, and the hole step of the screw hole should be a tapered wall formed corresponding to the taper of the bolt Can do.

  Furthermore, the present invention is suitably applied to a vacuum switch gear and a vacuum switchgear in which a connection portion between a lead conductor and a circuit conductor is molded with resin. According to this, since it is possible to suppress the occurrence of a partial gap on the contact surface between the lead conductor and the circuit conductor, it is possible to suppress the mold resin from entering the joint surface between the lead conductor and the circuit conductor. As a result, it is possible not only to prevent the mold resin from entering between the conductors of the connecting portion and increasing the electrical resistance between the conductors, but also the resin that has entered due to the impact caused by the opening / closing operation of the fixed electrode and the movable electrode is crushed, It is possible to solve the problem that the powder spreads in the gaps between the conductors of the connection part and the electrical resistance of the connection part is further increased.

  Also, in the case of a vacuum switchgear where the connection part between the lead conductor and the circuit conductor is molded with resin, a convex part is formed on the surface of the circuit conductor with which the end face of the lead conductor abuts, and this convex part is fitted It is preferable to form the recessed portion to be formed on the end face of the lead conductor. According to this, when the resin is molded, since the intrusion path of the mold resin that enters the contact surface between the end surface of the lead conductor and the circuit conductor is bent, the intrusion of the mold resin can be suppressed. In this case, you may make it form the recessed part by which the end surface part of an extraction conductor is fitted in the surface of the circuit conductor with which the end surface of an extraction conductor contacts.

  According to the present invention, it is possible to suppress the bolt shaft of the connecting portion connecting the lead conductor and the circuit conductor from being obliquely tightened with respect to the screw hole shaft into which the bolt is screwed.

  Hereinafter, embodiments of the vacuum switchgear of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an embodiment of the vacuum switchgear of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part of the present embodiment, and FIG. 3 is an enlarged view of the bolt of the present embodiment. This embodiment is an example in which the vacuum switchgear of the present invention is applied to a ground switch. However, the vacuum switchgear of the present invention is not limited to the ground switch, and it goes without saying that the vacuum switchgear can be applied to a vacuum switchgear having a connection portion for connecting a lead conductor and an external circuit conductor with a bolt.

  As shown in FIG. 1, the vacuum switchgear 1 of this embodiment includes a vacuum vessel 5 formed by sealing both ends of an insulating cylinder 2 with a fixed electrode side plate 3 and a movable electrode side plate 4. ing. A fixed electrode 6 and a movable electrode 7 are accommodated in the vacuum container 5 so as to face each other. The fixed electrode 6 is formed with a rod-shaped lead conductor 6b with an electrode tip 6a attached to the tip, and the movable electrode 7 is formed with a rod-shaped lead conductor 7b with a tip 7a attached to the tip. Has been.

  The lead conductor 6 b of the fixed electrode 6 passes through the fixed electrode side plate 3 constituting the wall of the vacuum vessel 5 and is drawn to the outside, and is fastened to the external flat circuit conductor 8 by bolts 9. An elastic member 10 such as a disc spring is interposed between the circuit conductor 8 and the bolt head of the bolt 9. An enlarged flange 6c is formed at the tip of the lead conductor 6b in contact with the circuit conductor 8, and the through hole of the fixed electrode side plate 3 is hermetically sealed in the flange 6c. Further, the outer periphery of the vacuum vessel 5, the connecting portion between the lead conductor 6b and the circuit conductor 8, and the circuit conductor 8 are insulated by a mold resin layer 11 such as an epoxy resin and have an integrated structure.

  On the other hand, the lead conductor 7 b of the movable electrode 7 is inserted through the through hole of the guide member 13 and drawn out of the vacuum vessel 5. The guide member 13 supports the lead conductor 7b so as to slide freely in the axial direction. Further, the guide member 13 is airtightly attached to the movable electrode side plate 4 constituting the vessel wall of the vacuum vessel 5 via the support member 14. Although not shown, an opening / closing mechanism for bringing the movable electrode 7 into and out of contact with the fixed electrode 6 is provided.

  Next, the configuration of the connecting portion between the lead conductor 6b and the circuit conductor 8 which is a characteristic part of the present embodiment will be described with reference to an enlarged view of FIG. As shown in FIG. 2, the lead conductor 6 b is formed in a rod shape from a copper material, and has a flange portion 6 c having an enlarged diameter at an end surface portion that becomes a joint portion with the circuit conductor 8. A screw hole 12 is formed along the axial direction of the lead conductor 6b. The end surface of the lead conductor 6 b is disposed in contact with the flat plate surface of the flat circuit conductor 8. The circuit conductor 8 is formed of, for example, a copper casting, and is formed with a convex portion 8a that is formed on the joint surface with the lead conductor 6b. The joint surface of the convex portion 8a is finished by grinding. A through hole 8b is formed in the center of the convex portion 8a. A bolt 9 is inserted into the through hole 8b, and a screw at the tip of the bolt is screwed into the screw hole 12, so that the lead conductor 6b and the circuit conductor 8 are tightened.

  As shown in FIGS. 3A and 3B, the bolt 9 of the present embodiment includes a small-diameter Wc distal end portion 9a, an unthreaded large-diameter Wd base portion 9b, and a distal end. A step portion of a tapered portion 9c that connects the portion 9a and the base portion 9b is formed. The length of the tip portion 9a is set to ta, the total length of the base portion 9b and the tapered portion 9c is set to tb, and the length of the tapered portion 9c is set to tc. On the other hand, as shown in FIG. 2, the screw hole 12 is formed with a screw portion 12a corresponding to the tip portion 9a of the bolt 9, and a tapered hole wall 12c having a shape corresponding to the taper portion 9c of the bolt. The maximum inner diameter Wb of the tapered hole wall 12c is formed larger than the diameter Wa of the threaded portion 12a. The maximum inner diameter Wb of the tapered hole wall 12c is formed to correspond to the outer diameter Wb of the base portion 9b of the bolt 9. A disc spring 10, which is a metal elastic member, is interposed between the circuit conductor 8 and the head of the bolt 9.

  With this configuration, according to this embodiment, when the bolt 9 is screwed into the screw hole 12, the taper portion 9c of the bolt 9 comes into contact with the taper hole wall 12c of the screw hole 12 and tightening is performed. Stop. Since the tapered portion 9c and the tapered hole wall 12c are formed symmetrically with respect to the axis, the axis of the bolt 9 and the axis of the screw hole 12 at the position where the tightening is stopped are coincident or parallel to each other. Accordingly, the shaft of the bolt 9 and the shaft of the screw hole 12 can be prevented from being tilted and tightened.

  Further, the tightening force of the bolt 9 depends on the elastic force of the disc spring 10, and the tightening force applied to the joint surface between the lead conductor 6b and the circuit conductor 8 is equalized regardless of the circumferential position of the bolt head. As a result, it is possible to prevent a partial gap from occurring on the contact surface between the end face of the lead conductor 6b and the convex portion 8a of the circuit conductor 8. That is, without increasing the tightening force of the bolt 9, it is possible to suppress contact between the conductors of the connecting portion of the lead conductor 6b and the circuit conductor 8, and no surface pressure concentration portion is generated.

  As a result, according to the present embodiment, it is possible to prevent the bolt 9 from loosening by suppressing a decrease in the axial force of the bolt 9 due to the relaxation of the conductor. Therefore, even if a large impact due to the opening / closing operation is repeatedly received, the looseness of the bolt 9 at the connecting portion can be suppressed, and the mechanical life of the vacuum switch gear can be prevented from being shortened.

  Furthermore, since it is possible to suppress the occurrence of a gap in the contact surface between the lead conductor 6b and the circuit conductor 8, it is possible to suppress the mold resin from entering the joint surface between the lead conductor 6b and the circuit conductor 8. As a result, it is possible not only to prevent the mold resin from entering between the conductors of the connecting portion and increasing the electrical resistance between the conductors, but also to crush the resin that has entered due to the impact associated with the opening / closing operation of the fixed electrode 6 and the movable electrode 7. Further, it is possible to prevent the problem that the resin powder spreads between the conductors of the connection part and further increases the electrical resistance of the connection part.

(Embodiment 2)
FIG. 4 shows a cross-sectional view of the characterizing portion of another embodiment of the present invention. The difference between the present embodiment and the first embodiment of FIG. 2 is the shape of the bolt 9 and the shape of the joining end of the lead conductor 6b, and the other points are the same as those of the first embodiment. Is omitted.

  As shown in FIG. 4, the bolt 9 of this embodiment is provided with a step portion 15 instead of the tapered portion 9 c of FIG. 3, and a hole step portion 16 is provided in the screw hole 12 corresponding to the step portion 15. And a concave portion 12d fitted to the convex portion 8a of the circuit conductor 8 is provided at the joint end portion of the lead conductor 6b.

  According to the present embodiment, when the bolt 9 is screwed into the screw hole 12, the step portion 15 of the bolt 9 abuts on the hole step portion 16 of the screw hole 12, and the tightening is stopped. The contact surfaces of the step portion 15 and the hole step portion 16 are formed so as to be orthogonal to the axis of the bolt 9 and the axis of the screw hole 12. Thereby, the axis | shaft of the volt | bolt 9 and the axis | shaft of the screw hole 12 in the position where clamping | tightening was stopped correspond or become parallel. Therefore, since it can prevent that the axis | shaft of the volt | bolt 9 and the axis | shaft of the screw hole 12 incline, it can have the same effect as Embodiment 1. FIG.

  Furthermore, according to the present embodiment, the concave portion 12d formed at the joining end portion of the lead conductor 6b is fitted into the convex portion 8a of the circuit conductor 8, so that the joint surface between the lead conductor 6b and the circuit conductor 8 is fitted. Even when a minute gap occurs, the path through which the mold resin enters the joint surface between the lead conductor 6b and the circuit conductor 8 can be bent and lengthened when the resin is molded.

  As a result, compared to the first embodiment, there is an effect that the mold resin can be further prevented from entering between the conductors of the connection portion.

(Embodiment 3)
FIG. 5 shows a cross-sectional view of the characterizing portion of still another embodiment of the present invention. The difference between the present embodiment and the first embodiment shown in FIG. 2 is the shape of the joining end of the lead conductor 6b, and the other points are the same as those of the first embodiment.

  As shown in FIG. 5, the present embodiment is characterized in that a concave portion 18 in which the joint end portion 17 of the lead conductor 6 b is fitted is provided in the joint surface portion of the circuit conductor 8. The recess 18 can be formed by forming a raised portion in a region where the recess 18 is formed when the circuit conductor 8 is formed using a mold, and then removing the raised portion.

  Therefore, according to this embodiment, in addition to the effect of Embodiment 1, there exists an effect that it can suppress further that mold resin penetrate | invades between the conductors of a connection part.

  As described above, according to each embodiment of the present invention, the bolt shaft of the connecting portion connecting the lead conductor and the circuit conductor is tightened obliquely with respect to the screw hole shaft into which the bolt is screwed. Can be suppressed. As a result, the gap between the conductors can be eliminated and the resin can be prevented from entering the bolt holes during molding.

  In addition, since the bubbles leaking from the through holes 8b can be blocked when the mold resin is cured and contracted, defects such as voids are not generated in the mold resin layer 11. In addition, the mold resin layer 11 does not generate a certain amount of internal stress, and does not crack. The setting of the stress can be easily controlled by changing the spring constant of the disc spring 10.

It is sectional drawing of the vacuum switchgear which concerns on one Embodiment of this invention. It is an expanded sectional view of the connection part of the extraction conductor and circuit conductor which concern on the characteristic part of embodiment of FIG. It is a detailed block diagram of the volt | bolt of embodiment of FIG. It is an expanded sectional view of the connection part of the lead conductor and circuit conductor which concern on the characteristic part of other embodiment of this invention. It is an expanded sectional view of the connection part of the lead conductor and circuit conductor which concern on the characteristic part of further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum switch gear 2 Insulation cylinder 3 Fixed electrode side plate 4 Movable electrode side plate 5 Vacuum container 6 Fixed electrode 6a Electrode tip 6b Lead conductor 7 Movable electrode 7a Electrode tip 7b Lead conductor 8 Circuit conductor 9 Bolt 9c Taper part 10 Belleville spring 11 Mold resin Layer 12 Screw hole 12c Tapered hole wall

Claims (6)

A vacuum vessel, a fixed electrode and a movable electrode housed opposite to each other in the vacuum vessel, an opening / closing mechanism for bringing the movable electrode into and out of contact with the fixed electrode, and the fixed electrode penetrating through a wall of the vacuum vessel A rod-shaped lead conductor that pulls out the outside, and a connecting portion that connects the lead conductor to an external circuit conductor,
The connection portion includes a screw hole drilled in the lead conductor, a through hole formed in the circuit conductor corresponding to the screw hole, and screwed into the screw hole through the through hole. A bolt for tightening the lead conductor, and an elastic member provided between the head of the bolt and the circuit conductor;
The bolt has a small-diameter distal end portion that is threaded, a large-diameter base portion that is not threaded, and a step portion that connects the distal end portion and the base portion.
The screw hole corresponds to the step portion so that the screw portion corresponding to the tip portion of the bolt, the enlarged diameter portion not screwed corresponding to the base portion of the bolt, and the step portion of the bolt abut. A vacuum switchgear formed by having a hole step portion formed as described above. The vacuum switchgear according to claim 1,
The stepped portion of the bolt is a tapered portion formed between the base and the tip.
The vacuum switchgear, wherein the hole step portion of the screw hole is a tapered wall portion formed corresponding to the tapered portion of the bolt. The vacuum switchgear according to claim 1 or 2,
A vacuum switchgear characterized in that the vacuum vessel and the connecting portion are molded of resin. The vacuum switchgear according to claim 3,
The circuit conductor has a convex portion formed on a surface with which the end surface of the lead conductor is in contact,
2. The vacuum switchgear according to claim 1, wherein the lead conductor is formed with a concave portion into which the convex portion of the circuit conductor is fitted on an end face of the lead conductor. The vacuum switchgear according to claim 3,
2. The vacuum switchgear according to claim 1, wherein the circuit conductor is formed with a recess into which the end face portion of the lead conductor is fitted on a surface with which the end face of the lead conductor is brought into contact. The vacuum switchgear according to claim 1,
The vacuum switchgear characterized in that the stepped portion of the bolt and the hole stepped portion of the screw hole are formed at positions where they abut within the range of elastic deformation of the elastic member.

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